What We Can Learn from the "Minnesota Starvation Experiment"
What it is.
Many people don’t know about the “Minnesota Starvation Experiment” that was conducted from November 1944 to December 1945 but it is a study that has frequently been cited in psychological and nutritional realms to point to the harmful effects of dieting and “semi-starvation”. The study by Ancel Keys and associates was designed to look at the physiological and physical effects of prolonged, famine-like semi-starvation on healthy men as a way to help understand how to help famine victims in Europe and Asia at the end of World War II. Participants were conscientious objectors of the war who were “willing to subject themselves to a year-long invasion of privacy, nutritional deprivation, and physical and mental hardship”. This might sound like a hard sell but it sure beats enlisting and fighting in a world war. The 36 participants were all between ages 22-33, all white, and had to follow specific physical and nutritional guidelines, walk 22 miles a week, keep a personal diary, and complete an extensive battery of tests that were given throughout the study. (Yes, there are some obvious methodological and ethical issues with this study. You have to remember it took place in 1944 and it was typical to only study white men and use them as the prototype for understanding all humans. Yes, it’s a very small sample. And, the ethics of starving people, even ones who agree to it, is also problematic in modern times. Despite these major issues, the findings are interesting and in some ways even more interesting to me because the ways these men responded are so different than what would have been typical given the cultural expectations of the time.)
How the study was done.
The study took place in several phases: control (12 weeks), semi-starvation (24 weeks), restricted rehabilitation (12 weeks), and unrestricted rehabilitation (8 weeks). During the control period, the men were on a controlled diet of 3200 calories a day which was adjusted to get them close to their “ideal” weight before the study started. During the semi-starvation period of 6 months, the men ate approximately 1560 calories a day. Their meals were mostly made up of foods that typify the diets of people in Europe at the latter stages of the war, including potatoes, rutabagas, turnips, bread, and macaroni. At the end of this period, Life Magazine did an article on the study and showed pictures of the men shirtless and looking bony. This is especially interesting to me because, by many diet standards of today, 1560 daily calories consisting of almost all carbohydrates would be considered a relatively “high” calorie diet composed of many “forbidden foods”. And yet, these men lost enough weight to be seen as bony and malnourished. During the restricted rehabilitation period, the men were subdivided into groups to test different levels of protein and vitamin supplements to test the best ways to engage in re-feeding. The last stage was the unrestricted rehabilitation period and caloric intake and food restriction were unrestricted but carefully recorded and monitored.
Psychological effects:
Food Obsession.
The study proved to be more difficult on the men psychologically than anticipated. Two people were dismissed from the study for a failure to maintain the dietary restrictions. During the semi-starvation and the rehabilitation periods, the men reported a preoccupation with food previously not experienced. Several subjects reported they read cookbooks obsessively, collected recipes and kitchen utensils, and would think about food constantly, and felt out of control when around food for fear they would binge. A few men did report episodes of binge eating and these were typically followed by a period of severe self-reproach and guilt. One subject began rummaging through garbage bins to see if he could find something he needed. This desire to hoard has been seen in people and animals who are deprived of food. Although the subjects had previously reported little interest in food before the experiment, 40% of them reported planning to focus on cooking after the experiment. Some of the men changed careers to one in the food industry when the experiment ended. Many of the men spent the day planning how and when they would eat their allocated food and would take much longer to eat their meals than before the experiment. Many would eat in silence as a way to devote total attention to their food consumption. Several men noted a conflict between wanting to gulp their food and eat it slowly to savor it. By the end of the starvation period of the experiment, some men would take almost two hours to eat a meal that previously would have been consumed in minutes. The subjects reported having a hard time identifying when they felt hungry or when they felt full and it took them months or years to be in touch with these feelings again. In addition, many men would begin to make unusual concoctions by mixing different foods together. Their use of tea and coffee increased to the point that it had to be limited to 9 cups per day. They also increased the use of sugar and salt dramatically and began chewing gum so excessively that it too had to be limited. Most of these behaviors are also commonly seen in people who experience eating disorders.
These behaviors are also seen in people who are dieting. If you’ve ever spent time with someone on a new diet (e.g., Paleo, Keto, Weight Watchers, Atkins) the obsession with food becomes clear. Dieters often spend much of their day focused on what they can and cannot eat, researching recipes, counting calories/ fat grams/ points, and generally having most of their world revolve around food, weight, and appearance. People lose touch with parts of themselves that are much more interesting to discuss and focus on than just what they are eating.
Mental Health impact.
The prolonged semi-starvation period produced significant periods of depression and hypochondriasis and most of the subjects reported periods of severe emotional distress and depression. They reported a drastic decrease in sexual interest and an increase in social withdrawal and isolation. Many of the men reported irritability and frequent outbursts of anger as well as an increase in anxiety. Additionally, some of the men reported an increase in apathy and neglected their personal hygiene. The participants reported feeling a decline in their concentration, comprehension, and judgment capabilities even as the standardized tests didn’t capture these changes. One subject experienced severe distress and engaged in self-mutilation and amputated 3 fingers with an axe during the rehabilitation phase, which many subjects said was the hardest phase for them to endure. Many of these psychological changes lasted for months after the rehabilitation phase leading researchers to conclude that the disturbances were more driven by the overall body weight change and need for weight restoration, not just the return to increased caloric intake at the moment. The semi-starvation process is more disruptive than we often think.
Physical impact.
The men showed marked declines in their physiological processes, indicative of a reduction in their metabolism (e.g., lower body temperature, respiration, and heart rate). Additionally, some subjects experienced edema (swelling) in their extremities. Several subjects reported reactions to the 6 months of semi-starvation including hair loss, decreased tolerance for cold temperatures, low energy, feeling weak, headaches, dizziness, gastrointestinal discomfort, and reduced strength. During the rehabilitation phase, the metabolism sped up again. However, the subjects who gained the most weight described being concerned with their increased sluggishness, “general flabbiness” and the tendency for fat to accumulate on their stomach and buttocks. These are also similar to the experiences of people with eating disorders. For the research subjects, their level of body fat and muscle were back to their pre-experiment levels after approximately a year.
